Looks like Phil's wish was granted. Bitmain has currently "Greyed Out" the S9 Buy button. No more sales for the moment it would appear. S7's are still available for those that are interested.
Look for batch 2 in a few days...
I see no reason why the S9 would be any different than any other Bitmain release. As soon as any new miner is released, the value clock on the hardware starts ticking down. They need to move as many units as they can as fast as they can. The upcoming halving and potential competition from BW (if they ever release anything to the public) could accelerate driving down the S9 price.
It's interesting how people theorize about the big player's strategies, including price/difficulty manipulation, intentional hardware delays, etc. But I think the situation is simpler than that. Hardware manufacturers need to mine early and ship quickly. Any other strategy is risky. You can't be sure that any manipulation attempt will work, and you can't know when a competitor might strike (although I acknowledge that Bitmain has no real competition now, except for maybe BW).
Of course some of this is wishful thinking on my part. I can't bring myself to pay the price Bitmain wants for the S9. But as it comes down, I'll be tempted, as well as others who are currently sitting on the fence.
Projected difficulty is still negative, but it's had to think it will last for for 7 more days.
We may get lucky this period, but when the S9s really start pumping out, it will be as bad or worse than the increases we saw just after the S7.
The power that Bitmain has over the mining market is so irritating. I really hope that some competition materializes...